Remove listener when given URL is visited after using chrome.tabs.onUpdated.addListener

Question

Here is my problem: I'm developing a Chrome extension for Gmail and needs to apply some changes when the extension is updated.

For example, I want to be sure that the extension will display an alert dialog within Gmail after the extension has been updated. This implies to check whether Gmail is already open in a Chrome window at the time of the update, and if not to create a listener in order to wait for Gmail to be loaded in the future and then to display the alert dialog.

The code below does just that. However, I cannot manage to remove the listener (chrome.tabs.onUpdated.removeListener?) when a new Gmail tab has been discovered.

background.js

     // [...] code before
    // Reload Tabs where Gmail is active
    function reloadTab(order) {
        chrome.windows.getCurrent(function(win) {
            var cwin = win.id;
            chrome.tabs.query({windowId: cwin}, function(tabs) {
                var countGmailTabs = 0;
                for (var i = 0; i < tabs.length; i++) {
                    var t = tabs[i].url;
                    if (t.match('mail.google.com')) {
                        countGmailTabs += 1;
                        if (order === 'set') {
                            chrome.tabs.reload(tabs[i].id);
                        } else if (order !== 'set') {
                            var GmailTab = tabs[i];
                            NewGmailURL(order, GmailTab);
                            return;
                        }
                    }
                }
                // Gmail not found !
                if (countGmailTabs < 1 && order !== 'set') {
                    chrome.tabs.onUpdated.addListener(function(tabId, changeInfo, tab) {
                        if ( tab.url.match('mail.google.com') && changeInfo.status === 'loading' ) {
                            NewGmailURL('update', tab);
                            return;
                            // Everything OK, now remove listener. How?
                        }
                    });
                }
            });
        });
    }
    // [...]

Thanks for your help!

For information, the alert dialog is displayed thanks to URL parameters.

// Modify Gmail URL
var updated = false;
    function NewGmailURL(param, ztab) {
        if (param === 'updated') {
            urlMyExtension = ztab.url.replace(urlGmail + '?query=update&', urlGmail +'?query=' + param + '&');
        } else {
            urlMyExtension = ztab.url.replace(urlGmail, urlGmail + '?query=' + param + '&');
        }
        if (!done && param !== 'updated') {
        chrome.tabs.update(ztab.id, {
            url: urlMyExtension,
            highlighted: ztab.highlighted
        }, null);
        updated = true;
        }
    }

[UPDATED] ANSWER

In case anyone meets the same problem, here is the answer thanks to @ExpertSystem:

// Listen to Tabs URL
    function myListener(tabId, info, tab) {
        if (tab.url.match("mail.google.com") && (info.status === "loading")) {
            NewGmailURL("update", tab);
            /* Now, let's relieve ourselves from our listener duties */
            chrome.tabs.onUpdated.removeListener(myListener);
            return;
        }
    }

// Reload Tabs where Gmail is active
function reloadTab(order) {
    chrome.tabs.query({ currentWindow: true }, function(tabs) {
            var countGmailTabs = 0;
            for (var i = 0; i < tabs.length; i++) {
                var t = tabs[i].url;
                if (t.match('mail.google.com')) {
                    countGmailTabs += 1;
                    if (order === 'set') {
                        chrome.tabs.reload(tabs[i].id);
                    } else if (order !== 'set') {
                        var GmailTab = tabs[i];
                        NewGmailURL(order, GmailTab);
                        return;
                    }
                }
            }
            // Gmail not found !
            if (countGmailTabs < 1 && order !== 'set') {
                chrome.tabs.onUpdated.addListener(GmailListener);
            }
    });
}

Answer 1

In order to be able to remove a listener do not implement it as an anonymous function. Implementing it as "named" function, allows you to reference it alter when calling removeListener().
E.g.:

/* Change this: */
chrome.tabs.onUpdated.addListener(function(tabId, changeInfo, tab) {...});

/* To this: */
function myListener(tabId, info, tab) {
    if (tab.url.match("mail.google.com") && (info.status === "loading")) {
        NewGmailURL("update", tab);
        /* Now, let's relieve ourselves from our listener duties */
        chrome.tabs.onUpdated.removeListener(myListener);
        return;
    }
});
chrome.tabs.onUpdated.addListener(myListener);

---

BTW, (not related to your problem, but) you are making a couple of superflous calls:

You don't need to get the current window and then get its tabs, like this:

chrome.windows.getCurrent(function(win) {
    var cwin = win.id;
    chrome.tabs.query({windowId: cwin}, function(tabs) {
    ...

You can do it in one call, like this:
_{(See, also, chrome.windows.getCurrent())}

chrome.window.getCurrent({ populate: true }, function(win) {
    var tabs = win.tabs;
    ...

Or even like this:
_{(See, also, chrome.tabs.query())}

chrome.tabs.query({ currentWindow: true }, function(tabs) {
...